JP2013184484A - Sensor abnormality detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost, weight and an increase in volume while preventing a function loss caused by a transient communication abnormality in a sensor abnormality detection device connected to a microcomputer from a sensor via a power supply IC.SOLUTION: In a sensor abnormality detection device 10, a power supply IC 2 supplies power to a sensor 1 having a self-diagnostic function by a power line L1 and receives a current superposition signal. When a sensor signal is transmitted to a microcomputer 3 via the power supply IC 2 and the microcomputer 3 detects a communication abnormality, the power supply IC 2 interrupts power supply to the pressure sensor 1 once and resumes the power supply. Thus, the restart of the pressure sensor 1 and the recovery of the communication abnormality are tried several times, thereby generating no function loss caused by a transient communication abnormality, making the wiring of the sensor 1 have a simple two-wire type and reducing cost, size and weight.

Description

  The present invention belongs to the technical field of sensor abnormality detection using a microcomputer.

  Patent Document 1 discloses a configuration of an airbag device control device (ECU) that receives a sensor signal superimposed on a current supplied to a satellite device including a G sensor as a sensor abnormality detection device. When the excessive current supplied from the control device to the satellite device exceeds a predetermined time, the power supply to the satellite device is stopped by operating the protection circuit to protect the power supply circuit. . Also, if an overcurrent is detected temporarily, the current is reduced to the limit value and the current communication is continued. Can be restored to a normal value.

JP 2001-39263 A

  However, in the above-mentioned background art, once the power supply to the satellite device (the sensor referred to in the present invention) is stopped, there is no function for restarting the satellite device and restoring it, and the sensor from the satellite device is not provided. The signal remains unavailable.

  On the other hand, when an attempt is made to detect sensor abnormality in a configuration having a sensor having a self-diagnosis function, a power supply IC that receives a measurement signal superimposed on DC power supplied to the sensor, and a microcomputer that receives measurement data from the power supply IC. Usually, the sensors are connected in a three-wire system. That is, when there is an abnormality in the measurement data received by the microcomputer from the sensor via the power supply IC, a signal line for starting the sensor self-diagnosis function must be connected from the microcomputer to the sensor. Then, three lines are connected to the sensor: a signal line for instructing a self-diagnosis from the microcomputer, a power line supplied with power from the power supply IC and superimposing a signal on the current, and a ground line to the ground. .

  As a result, it is necessary to use a sensor with a 3-pin terminal for the sensor, and when considering the trouble of wiring the signal line that instructs the self-diagnosis from the microcomputer, an increase in weight and volume and an increase in cost occur. It is inconvenient.

  Therefore, the present invention provides a sensor abnormality detection device that can restore the function of a sensor as long as it is temporary even if there is a communication abnormality from the sensor with almost no increase in cost, volume, and weight. Is a problem to be solved.

  In order to solve the above-mentioned problems, the inventors have invented the following solution means. In this section, the configuration of the main means among the solving means will be described, and the effects brought about by the configuration will be briefly described. The description in this section corresponds to the main claim described in “Claims” at the time of filing of the present application, and the reference numerals in parentheses attached to the components correspond to the reference numerals in the drawings. Yes.

(Configuration of the present invention)
The present invention is a sensor abnormality detection device (10) having a sensor (1), a power supply IC (2), and a microcomputer (microcontroller) (3).

  Here, the microcomputer (3) has a self-diagnosis means (S12) for self-diagnosis of failure at the time of start-up, and superimposes the diagnosis result and the sensor measurement signal by the self-diagnosis means (12) on the current communication. Has the function to transmit. The power supply IC (2) has power supply means (S11) for supplying DC power to the sensor (1), and has a function of receiving this current communication from the sensor (1) by asynchronous current communication. The microcomputer (3) has data receiving means (S15) for receiving measurement data based on the sensor measurement signal via the power supply IC (2), and has a function of generating an output signal based on the measurement data.

  The sensor abnormality detection device (10) is characterized in that the microcomputer (3) includes a sensor determination means (S13), a communication determination means (S14), a reset means (S32), a reset restriction means (S33), and an output stop means ( S22, S35). Here, the two output stopping means (S22, S35) may be configured to share at least a part of each other.

  First, the sensor determination means (S13) is means for detecting that the sensor failure is determined by the self-diagnosis means (S12) of the sensor (1). Next, a communication determination means (S14) is a means for determining whether or not there is a communication abnormality in the measurement data. The reset means (S32) instructs the power supply IC (2) to temporarily stop the power supply to the sensor (1) when the communication judgment means (S14) determines that there is a communication abnormality. It is a means to resume. On the other hand, the reset limiting means (S33) is a means for limiting the number of operations of the reset means (S32) until a predetermined determination condition is satisfied. The output stop means (S22, S35) is when the sensor failure determination is detected by the sensor determination means (S13) and when the reset means (S32) is stopped by the reset restriction means (S33). And means for stopping the generation of the output signal in any case.

  Here, the determination condition in the reset limiting means (S33) can be, for example, that the integrated value of the number of detected communication abnormalities reaches a predetermined specified number. If such a determination condition is satisfied, the communication limit is not temporary, but frequently occurs, and it should be considered that there is a communication failure. judge.

  In other words, the sensor abnormality detection device (10) has both the sensor failure and communication failure determination functions described above, and the microcomputer (3) can be used when either sensor failure or communication abnormality is determined. Has a function to stop the output signal.

(Operational effect of the present invention)
In the sensor abnormality detection device (10), if the sensor itself is found to be defective by the self-diagnosis means (S12) incorporated in the sensor, this is notified from the sensor (1) via the power supply IC (2). It is transmitted to the microcomputer (3). Then, the microcomputer (3) detects that the sensor failure has been determined, operates the output stopping means (S22), and stops generating the output signal. As a result, control of an external device or the like based on erroneous measurement data with a sensor failure is prevented.

  On the other hand, even if the self-diagnosis of the sensor (1) is normal, if a communication abnormality is detected by the communication determination means (S14) of the microcomputer (3) due to noise or for some reason, the microcomputer (3) The power supply IC (2) is instructed to reset the sensor (1). That is, the reset means (S32) of the microcomputer (3) issues a command signal to the power supply IC (2), temporarily stops the power supply from the power supply IC (2) to the sensor (1), and then restarts. Then, the sensor (1) restarts, but at that time, self-diagnosis is performed again by the self-diagnosis means (S12) of the sensor (1). If the diagnosis result of the self-diagnosis means (S12) is normal, the sensor (1) resumes sending a normal measurement signal to the power supply IC (2). The power supply IC (2) relays the measurement signal from the sensor (1) and transmits it to the microcomputer (3) as measurement data.

  In the microcomputer (3), the communication determination means (S14) constantly monitors the measurement data, and when it is determined that there is a communication abnormality again, the reset means (S32) operates again until a predetermined determination condition is satisfied. The sensor (1) is restarted as described above. This determination condition is incorporated in the reset limiting means (S33) of the microcomputer (3), and the reset limiting means (S33) limits the number of times the reset means (S32) is operated until a predetermined determination condition is satisfied. There is a function.

  That is, when the communication abnormality is detected many times and the predetermined determination condition is satisfied, the communication abnormality is not temporary, and normal measurement data can no longer be obtained from the sensor (1). In this state, the reset limiting means (S33) of the microcomputer (3) determines. Then, the microcomputer (3) recognizes that the communication abnormality from the sensor (1) is not temporary, operates the output stop means (S35), and also stops the generation of the output signal. As a result, it is possible to prevent external devices from being controlled based on measurement data that is not normal due to a communication failure.

  Therefore, according to the sensor abnormality detection device (10) of the present invention, even when a communication abnormality is detected by the communication determination means (S14) of the microcomputer (3), the reset means (S32) operates and the sensor (1 ) Until the communication recovery by restart is satisfied. Since the sensor (1) automatically performs self-diagnosis of the sensor function by the self-diagnosis means (S12) every time it is restarted, a signal that instructs the sensor (1) to perform self-diagnosis directly from the microcomputer (3) No line is required.

  As a result, the sensor (1) is a cheaper, smaller and lighter two-pin type, and there is no need for a signal line from the microcomputer (3) to the sensor (1) for self-diagnosis. Since it can be maintained, there is an effect that the cost can be reduced and the size and weight can be reduced. Nevertheless, the sensor function can be recovered for a temporary communication abnormality, and the sensor abnormality detection device (10) itself only in the case of a communication failure in which communication abnormality occurs frequently enough to satisfy a predetermined determination condition. Can be deactivated.

  That is, according to the sensor abnormality detection device (10) of the present invention, the wiring to the sensor (1) is a simple two-wire system, and the cost can be reduced and the size and weight can be reduced. There is an effect that can be avoided.

FIG. 1 is a block diagram showing a schematic configuration of an ABS control device as a first embodiment. The flowchart which shows the operation logic principal part in Example 1.

  Embodiments that can be taken by the sensor abnormality detection device of the present invention will be described clearly and sufficiently in the following description so that those skilled in the art can understand the present invention as much as possible. At the time of filing of the present invention, the inventor considers that the best embodiment is disclosed among the following examples or modifications thereof.

  As the sensor abnormality detection device as the first embodiment of the present invention, an ABS (anti-lock brake system) control device mounted on an automobile is taken up and exemplified below.

(Device configuration)
As shown in FIG. 1, the ABS control device 10 (as a sensor abnormality detection device) of the present embodiment includes a pressure sensor 1 that measures the brake hydraulic pressure of the ABS, a power supply IC 2 that supplies power to the pressure sensor 1, and an ABS. And a microcomputer 3 that outputs an output signal for control.

  An ASIC (not shown) is attached to the pressure sensor 1, and the pressure sensor 1 has a self-diagnosis function by the self-diagnosis means S12 (see FIG. 2) and a function of transmitting a signal to the power supply IC 2 by current communication. Have. That is, the pressure sensor 1 has a function of self-diagnosis of its own set of functions when the pressure sensor 1 is started by the self-diagnosis means S12, and further sends a signal of the diagnosis result, and then superimposes the pressure measurement signal on the current amount. A transmission function for generating and continuing to the power supply IC 2 is provided.

  That is, power is supplied to the pressure sensor 1 from the power supply IC 2 through the DC power supply line L1, while the pressure sensor 1 receives the self-diagnosis result from the pressure sensor 1 from the built-in ASIC (not shown) through the DC power supply line L1. The indicated signal and the pressure measurement signal are transmitted to the power supply IC 2 by asynchronous current communication. That is, the power supply IC 2 performs asynchronous current communication between the function of supplying DC power to the pressure sensor 1 by the power supply means S11 (see FIG. 2) through the DC power supply line L1, and the self-diagnosis signal and pressure measurement signal from the pressure sensor 1. With a receiving function.

  Here, the shape of the pressure sensor 1 is two pins, and one pin (not shown) is connected to the power supply terminal (not shown) of the power supply IC 2 by the DC power supply line L1, and the other pin (not shown). ) Is grounded to the vehicle body (not shown) by a ground wire G. That is, for the pressure sensor 1, a two-wire connection method is adopted.

  The microcomputer 3 has a function of receiving measurement data based on a measurement signal from the pressure sensor 1 via the power supply IC 2 and a function of generating an ABS control signal as an output signal based on the measurement data. In the following description, if the reference numeral after the constituent element is a numeral only, the constituent element in FIG. 1 is referred to, and if the reference numeral with “S” indicating the number of the processing step or determination step is used, FIG. Please refer to the flowchart.

  That is, the microcomputer 3 includes a sensor determination unit S13, a communication determination unit S14, a reset unit S32, and a reset restriction unit S33, an output stop unit S22 due to a sensor failure, and an output stop unit S35 due to a communication failure. It has.

  First, the sensor determination unit S13 is a unit that detects that the sensor failure is determined by the self-diagnosis unit S12 of the pressure sensor 1. That is, the microcomputer 3 has a function of receiving a signal indicating the result of the self-diagnosis transmitted by the ASIC (not shown) of the pressure sensor 1 via the DC power supply line L1, the power supply IC2, and the measurement data line L2. The sensor determination means S13 incorporated in the microcomputer 3 has a function of detecting that if the signal indicating the result of the self-diagnosis of the pressure sensor 1 indicates a sensor failure.

  Next, the communication determination unit S14 is a unit that determines whether or not there is a communication abnormality in the pressure measurement data from the pressure sensor 1. That is, the communication determination unit S14 receives the pressure measurement signal transmitted from the ASIC (not shown) of the pressure sensor 1 through the DC power supply line L1, the power supply IC2, and the measurement data line L2 in order. The pressure measurement signal is converted into pressure measurement data when transferred to the microcomputer 3 via the power supply IC 2. The communication determination unit S14 has a function of examining the received pressure measurement data, and has a function of determining whether a communication abnormality has occurred.

  The reset means S32 is a means for instructing the power supply IC2 through the on / off signal line L3 to stop and restart the power supply to the sensor 1 when the communication determination means S14 determines that there is a communication abnormality. is there. On the other hand, the reset limiting unit S33 is a unit that limits the number of times the reset unit S32 is operated until a predetermined determination condition is satisfied.

  The output stop means S22 and S35 are controlled by the microcomputer 3 both when the sensor determination means S13 detects the sensor failure and when the reset restriction means S33 stops the reset means S32. It is means for stopping the generation of signals. Here, the determination condition in the reset limiting unit S33 may be, for example, that the integrated value of the number of detected communication abnormalities reaches a predetermined specified number. It should be noted that the output stop means S22 due to sensor failure and the output stop means S35 due to communication failure are the same as each other, and it is activated only by the determination of the sensor failure or the determination of the communication failure. It is only different. In FIG. 2, for the convenience of drawing, output stop means S22 due to sensor failure and output stop means S35 due to communication failure are merely separated.

  That is, the sensor abnormality detection device 10 of the present embodiment has both the above-described sensor failure and communication failure determination functions, and the microcomputer 3 controls the microcomputer 3 when either of the sensor failure and communication failure is determined. Has a function to stop the output signal. These determination logics will be described in the next section.

(Operating logic)
Since the ABS control device 10 of this embodiment is mounted on a vehicle (not shown) as described above, the operation logic thereof is that the power device (not shown) of the vehicle is started and the ABS control device. 10 starts from the stage when power supply starts. In this section, the operation procedure of the ABS control apparatus 10 will be described with reference to the flowchart of FIG. 2, so that, for example, the self-diagnosis means S12 is simply used in step S12. "Is simply called" Step S ** ".

  As shown in FIG. 2, when the operation logic starts, the power supply IC 2 rises and power supply to the pressure sensor 1 is started in step S11, and this is notified to the microcomputer 3 through the measurement data line L2. In step S12, the self-diagnosis function is automatically activated when the pressure sensor 1 is activated, and a signal indicating the diagnosis result is sent from the pressure sensor 1 to the microcomputer 3 via the power supply IC2. If there is no abnormality in the self-diagnosis of the pressure sensor 1, a signal indicating the pressure measurement value is subsequently sent from the pressure sensor 1 to the microcomputer 3 via the power supply IC2.

  In determination step S13, the microcomputer 3 determines whether or not there is an abnormality in the diagnosis result of the pressure sensor 1. If it is determined that there is no abnormality in the self-diagnosis result, the measurement data sent from the pressure sensor 1 to the microcomputer 3 via the power supply IC 2 in the next determination step S14 is examined according to a predetermined rule, and communication abnormality is detected. A determination is made as soon as there is. If it is determined that there is no communication abnormality, it is assumed that normal measurement data is obtained, and the process proceeds to step S15, where the microcomputer 3 generates an output signal for ABS control based on the measurement data. In subsequent step S16, the data communication in which the microcomputer 3 receives the measurement data from the pressure sensor 1 via the power supply IC 2 is continued, and the logic returns to step S14. In this way, steps S14 to S16 are repeated in a normal operation state of the ABS control apparatus 10.

  On the other hand, if it is determined in the previous determination step S13 that the self-diagnosis result of the pressure sensor 1 is abnormal, the microcomputer 3 recognizes that the pressure sensor 1 has failed in step S21. In subsequent step S22, generation of a control signal that is an output based on a measurement signal from the pressure sensor 1 is stopped, and the brake control by the ABS control device 10 is prohibited by itself.

  Conversely, even if it is determined that there is no abnormality in the pressure sensor 1 in the determination step S13, if it is determined in the next determination step S14 that there is a communication abnormality, the power supply from the power supply IC 2 to the pressure sensor 1 is temporarily turned on. The operation of stopping and restarting and restarting the pressure sensor 1 is repeated several times.

  That is, the operation logic proceeds to step S31, accumulates (counts up) the number of detected communication abnormalities, and holds the accumulated value. In step S32, the microcomputer 3 prepares a command signal for shutting off the power supply to the pressure sensor 1 to the power supply IC2. In the next determination step S33, it is determined whether or not the integrated value of the number of communication abnormalities in the above-described step S31 has reached a predetermined specified number.

  If the integrated value of the number of communication abnormalities has not reached the predetermined specified number in this determination step S33, the above-described shut-off command is transmitted from the microcomputer 3 to the power supply IC2, and the power supply IC2 supplies power to the pressure sensor 1. Once stopped, the power supply is resumed after a predetermined short time. Then, the operation logic returns to step S11 and tries to restart the pressure sensor 1. As a result, if the restart of the pressure sensor 1 is successful and the communication to the microcomputer 3 is restored normally, the operation of the ABS control device 10 can be continued without being lost.

  However, if communication abnormality occurs frequently, and the integrated value of the number of communication abnormalities reaches a predetermined specified number in the determination step S33, the operation logic proceeds to the next step S34 to determine a communication failure, In step S35, the control output by the microcomputer 3 is stopped. That is, the ABS control device 10 stops generating the control signal and prohibits the brake control by this control signal itself.

  As a result, the ABS that is the control target of the ABS control device 10 according to the present embodiment can avoid the inconvenience of erroneous control due to either a sensor failure or a communication failure.

  When the control is prohibited in either step S22 or step S35, an alarm lamp is lit on the vehicle instrument panel through a monitor device (not shown) so as to encourage the driver to perform careful driving and prompt repair. It has become.

(Points of action and effect)
As described above, in the ABS control device 10 according to the present embodiment, when the sensor itself is defective due to the self-diagnosis function incorporated in the pressure sensor 1, that fact is transmitted from the pressure sensor 1 via the power supply IC 2. Is transmitted to the microcomputer 3. As a result, the microcomputer 3 stops generating the output signal for the ABS control, so that the brake control based on erroneous measurement data is not performed.

  On the other hand, even if the self-diagnosis result of the pressure sensor 1 is normal, if a communication abnormality is temporarily detected for some reason, such as noise mixing or synchronization loss, the microcomputer 3 instructs the power supply IC 2 to After temporarily stopping the power supply to the sensor 1, the power supply is resumed. Then, the pressure sensor 1 performs self-diagnosis again at the restart, and resumes sending a normal measurement signal to the power supply IC 2 if the diagnosis result is normal.

  In this way, if the pressure sensor 1 restarts normally and the communication abnormality is transient and does not occur frequently, the ABS controller 10 functions only for a short time required for restarting the pressure sensor 1 and the like. However, it can continue to operate with its normal functions. However, if the communication error is detected many times and the integrated value of the number of communication error detection exceeds the specified number, the communication error is not a temporary condition but a communication failure. The microcomputer 3 determines that normal measurement data from 1 cannot be obtained. As a result, it is assumed that the ABS control device 10 cannot function normally, the ABS control function is stopped, and brake control based on an erroneous signal is prevented.

  Therefore, according to the present embodiment, the stop and restart of the pressure sensor 1 and the accompanying sensor self-diagnosis are performed by once stopping and restarting the power supply from the power supply IC 2 to the pressure sensor 1 sensor. Therefore, in the ABS control device 10, it is not necessary to provide a separate signal line for instructing the pressure sensor 1 to perform a self-diagnosis directly from the microcomputer 3. As a result, the pressure sensor 1 can be an inexpensive, small and light two-pin type, and the connection method to the pressure sensor 1 is a simple two-wire type and does not require an extra signal line. There is an effect that the weight can be reduced. Nevertheless, the function recovery by restarting the pressure sensor 1 can be attempted up to a predetermined number of times for a temporary communication abnormality, so that the function of the ABS control device 10 stops due to a temporary communication abnormality. Such inconvenience is avoided.

(Various variations)
As a modification of the present embodiment, for example, the logic corresponding to steps S31 to S33 in FIG. 2 is modified so that the number of detected communication abnormalities per predetermined time reaches a predetermined specified number of times, The moving average may reach a predetermined value. Of course, two or three of these communication abnormality determination methods and the communication abnormality determination method in the first embodiment can be combined by logical product or logical sum.

  When the microcomputer 3 stops outputting the control signal, it is preferable to save power by stopping the supply of electrodes from the power supply IC 2 to the pressure sensor 1. Furthermore, the power supply IC 2 can also be stopped to reduce power consumption, and the microcomputer 3 can also be stopped or put to sleep, thereby further saving power.

(Remarks)
In addition, the above has illustrated specific embodiment of this invention, and the scope of this invention is not restricted to the above Example and various deformation | transformation aspects. For example, the present invention can be applied to a sensor abnormality detection device having various sensors other than the pressure sensor 1.

  Further, the target for incorporating the sensor abnormality detection device of the present invention is not limited to vehicles such as automobiles, vehicles (vehicles), or moving objects. For example, it can be appropriately incorporated into various devices and systems installed in factories and buildings, and conversely, it can also be incorporated into portable devices incorporating various sensors.

10: ABS control device (as the sensor abnormality detection device of Example 1)
1: Pressure sensor (as sensor) 2: Power supply IC 3: Microcomputer L1: DC power supply line (Asynchronous communication with pressure measurement signal superimposed on current)
L2: Measurement data line L3: On / off signal line G: Ground line S11: Power supply means S12: Self-diagnosis means S13: Sensor determination means S14: Communication determination means S15: Data reception means S22: Output stop means S32: Reset means S33: Reset limiting means S35: Output stopping means

Claims (4)

A sensor (1) having self-diagnosis means (S12) for self-diagnosis of the presence or absence of a failure at start-up, superimposing a diagnosis result by the self-diagnosis means (S12) and a sensor measurement signal on current, and transmitting by current communication;
A power supply IC (2) having power supply means (S11) for supplying DC power to the sensor (1) and receiving the current communication from the sensor (1) by asynchronous current communication;
A microcomputer (3) having data receiving means (S15) for receiving measurement data based on the sensor measurement signal via the power supply IC (2), and generating an output signal based on the measurement data;
In the sensor abnormality detection device (10) having
The microcomputer (3)
Having sensor determination means (S13) for detecting that the sensor failure is determined by the self-diagnosis means (S12) of the sensor (1);
Communication determination means (S14) for determining whether or not there is a communication abnormality in the measurement data, and if the communication determination means (S14) determines that there is a communication abnormality, command the power supply IC (2). Reset means (S32) for temporarily stopping and restarting power supply to the sensor (1), and reset restricting means for limiting the number of operations of the reset means (S32) until a predetermined determination condition is satisfied ( S33)
In any case, the sensor determination means (S13) detects the sensor failure and the reset restriction means (S33) stops the reset means (S32). It has an output stop means (S22, S35) for stopping the generation of the output signal,
Sensor abnormality detection device (10). The determination condition in the reset limiting means (S33) is:
The integrated value of the number of detections of the communication abnormality reaches a first specified number of times;
The number of detections of the communication abnormality per predetermined time reaches a second specified number of times;
The moving average of the number of detections per predetermined time reaches the third specified number of times,
At least one,
The sensor abnormality detection device (10) according to claim 1. When the microcomputer (3) stops the output signal, the microcomputer (3) also stops the electrode supply from the power supply IC (2) to the sensor (1).
An abnormality detection device (10) according to one of claims 1 and 2. When the microcomputer (3) stops the output signal, the microcomputer (3) also stops the power supply IC (2).
The abnormality detection device (10) according to claim 3.

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